Shut-down device for well pumping engines



A.B.CASE

June 21, 1938.

SHUT-DOWN DEVICE FOR WELL PUMPING vENGINES Filed June 13, 1936 m T A\N C E m A HIS ATTORNEY Patented June 21, 1938 UNlTED STATES SHUT-DOWN DEVICE FOR WELL PUMPING ENGINES Arthur B. Case, Snomac, Okla, assignor to The Texas Company, New York,

tion of Delaware N. Y., a corpora- ApplicationJune 13, 1936, Serial No. 84,999

3 Claims.

My invention relates to well pumping apparatus, and more particularly to an apparatus for automatically stopping an engine used in' pumping the well in the event of failure or breakage of parts of the equipment, or other accidental occurrences during pumping operations.

In pumping oil wells, failure of certain parts of the equipment frequently occurs. For in- A stance, the string of sucker rods or polish rods may break or separate. Also, the drive belt may break or slip, causing the engine to run away or suddenly speed up due to the sudden release of the load to which it was subjected before such accident. 'It quite often happens that the operator or attendant is not near enough to shut down the pumping engine at the time of such occurrence, and serious damage may, and frequently does, result.

The primary object of my invention is to provide an apparatus which will automatically shut down an engine in case of any of the aforementioned accidents, and thereby prevent any serious damage which might otherwise occur.

In carrying out my invention I have provided a tripper arm situated near the polish rod and connected by means of a cable to the engine valve which is open during normal operation.

. Should one of the rods break, however, the arm will be tripped and the valve will automatically close. I have also provided a movable arm connected by a cable to the engine valve and mounted directly under the lower side of the drive belt in such a manner that should the belt break it will fall upon the arm and cause the valve to close. For a better understanding of my invention, reference may be made to the accompanying drawing in which Figure 1 is a side View showing my apparatus in operative position.

Figure 2 is a plan View taken on the line 22 of Figure 1.

Figure 3 is an enlarged sectional elevation of the engine valve and governor.

Figure 4 is a side elevation of the arm on the lower side of the drive belt.

Referring to the drawing, a polish rod I0 is adapted to be reciprocated vertically in a well by any conventional means, such as that in which an internal combustion or gas engine shown 50 diagrammatically at Illa drives a walking beam to which the rods are attached. Since the englue and beam do not form a part of my invention they have not been fully illustrated. A clamp II is secured to the polish rod in, and a pin I2 is secured to the clamp II. A tripper arm I3 is pivotally mounted on bolt through a double bracket l6 which is attached to a post I! erected on the derrick fioor IS. The front end of the tripper arm l3 extends closely adjacent to the polish rod [0, and is arranged to be slightly above the pin I2 when the rods ID are at the top of a normal stroke. A loose block I 9 is normally held in place on the bracket I6 and over the back end of the tripper arm I3 by a pin 20 which is rigidly secured to arm I3 and extends upwardlytherefrom and into a hole 2| in block I 9. The loose block 19 is fastened to a rigid block 22 by flexible wires 23 and is connected to valve 24 located in the engine fuel supply line 25by a wire cable 26 passing over pulleysZl, 28 and 29. A weight 29a is attached to the cable 26 and hangs between the pulleys 28 and 29. 'Shouldthe rods part, the upper rod I0 is thrown'upwardly, causing the pin l2 to strike and raise the front end of the tripper arm I3, withdrawing the pin 20 from the block l9 and allowing the block [9 and wire 26 to travel toward the engine house, not shown. The weight 29 will fall and a lever arm 30 on engine valve 24 will be pulled upwardly, allowing the valve to close thereby shutting off the fuel supply to the engine.

' The valve 24, shown more clearly in Figure 3, and which is also shown in my U. S. Letters Patent No. 1,739,207 granted December 10, 1929, comprises the lever arm 30 pivoted to the valve housing at 30a and adapted to cooperate with the valve stem or rod 3| to hold the valve 33 normally open against the force of valve spring 33a which biases the valve toward its closed position. The valve stem 3| is provided with a small lug 34 adapted to engage a similar lug 34a on the arm 30 when the arm is in its normal or horizontal position and the valve 33 will thus be held open. However, when the arm 30 is pulled upwardly the lugs 34 and 34a will be disengaged and the valve will be closed by the spring 330..

A governor 35, which is of the ordinary centrifugal type driven by the engine, not shown, is used to automatically shut down the engine should the enginebe suddenly accelerated beyond a predetermined speed. In this arrangement, fuel is supplied to the engine at the desired amount, according to the load which the engine must carry to maintain a certain constant speed. A release pin 36 is secured to and depends from the lever arm 30, and is of a length such that when the fuel supply valve 24 is open the pin extends close to but slightly above the i4 passing governor disc 31 while running at normal speed. The length of the pin 36 depending from the arm 30 may be adjusted so that in case it is desired to run the engine at a relatively high speed, the pin will not be contacted by the governor disc 31 unless a still higher undesired speed is attained. When the motor is suddenly speeded up due to some unintended event such as the breakage or slipping of the drive'belt, the governor disc is raised and strikes the pin 36 thus tripping the valve 24 to its closed position, shutting ofi the fuel supply to the engine.

Another feature of my invention comprises a movable arm 38 lightly mounted on a post or block 39 which is secured to the derrick floor I8 directly under the lower side of the drive belt 40. The arm 38 is mounted on a pin 4| projecting from the post 39, and is attached to the post by a nail 42 driven through arm 38 and into the post 39 only to such depth as is necessary to support the arm in a horizontal position. A wire cable 43, passing over pulleys 44 and 45 is attached at one end to arm 38, and is connected at its other end to cable 26 and thus to lever 30 of engine valve 24 as shown in Figure 1. Should the belt 40 break it will fall upon the movable arm 38, forcing it downwardly, causing the wire '42 to pull the arm 30 upwardly allowing the spring 33a to close the valve 24, thus stopping the engine.

Obviously many modifications and variations of my invention may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

\ I claim:

1. In combination with a reciprocatory pump rod and driving means forsaid rod including an internal combustion engine, a valve in the fuel supply line in saidengine, means for closing said valve in an emergency, said means including a supporting post, a tripable member pivotally mounted on said post and disposed adjacent said pump rod, a pin secured to said pump rod, and a connection between said member and said valve, the arrangement being such that in the event of a sudden abnormal increase in speed of said driving means, said pin will strike and move said tripable member to close said valve.

2. In combination with a reciprocatory well pump rod and an engine for actuating said rod, a valve for controlling the admission of fuel to said engine, a tripper arm disposed adjacent said rod, means connected to said rod for engaging and moving said arm on a predetermined -overtravel of said rod, releasable means for biasing, said valve toward its closed position, and means connecting said arm to said releasable means so that the movement of said arm will cause said biasing means to close said valve.

3. In combination with a string of reciprocatory well pump rods and an-engine for actuating said string, a valve for controlling the admission of fuel to said engine, a fixed bracket, an arm pivotally'mounted on said bracket, one end of said arm extending closely adjacent to said rod string, a pin secured to the other end of said arm, ad'ooseblock normally "resting on said bracket and provided with an opening adapted to receive said pin, a cable for connecting said block to said valve, a weight supported by said cable, and 'means attached to said rod string for engaging and raising the extended end of said arm so as to pull said pin from the opening in said block in case said rod string should part, the arrangement being such that on the release of said block by said pin, said weight will fall, causing said valve to close.

ARTHUR 13. CASE. 

